Which imaging modality is commonly used to assess the suspensory ligament and distal sesamoidean ligaments, and what findings indicate injury?

Which imaging modality is commonly used to assess the suspensory ligament and distal sesamoidean ligaments, and what findings indicate injury?

• A. Radiographs showing bone remodeling.
• B. Magnetic resonance imaging showing soft tissue edema only.
• C. Ultrasonography showing fiber disruption, swelling, hypoechoic or heterogeneous areas, and core lesions.
• D. Computed tomography showing cortical defects only.

Answer: (C)

Ultrasound is the imaging method of choice for evaluating the suspensory ligament and distal sesamoidean ligaments because it directly images the soft tissues of the palmar/plantar aspect of the fetlock and can show fiber integrity in real time. In a healthy ligament, the fibers run parallel and appear echogenic with a uniform texture. When injury occurs, you see fiber disruption with loss of that orderly parallel pattern, surrounding swelling from inflammation, and areas within the ligament that are hypoechoic (darker) or heterogeneous, indicating edema, hemorrhage, or partial tearing. A focal central defect, known as a core lesion, is a characteristic finding that reflects a more focal, severe disruption within the ligament. These ultrasound findings collectively point to injury of the suspensory apparatus. Other imaging modalities are less practical for this purpose: radiographs mainly reveal bone changes, MRI can show soft-tissue edema but is less accessible and more costly, and CT emphasizes cortical bone rather than the ligament's fibrous structure.